Millions of people perceive the specter of spy and law enforcement agencies searching their calling patterns, and seeking access to communications content. The prospect that a deeply politicized-indeed, radical-administration may share personal data with the IRS or the Department of Health and Human Services compounds such fears.

As with so much in our legal and moral traditions, balancing multiple considerations may best address our privacy concerns. I suggest three privacy principles, keyed to specific contexts that call for different levels of privacy protection: We need more privacy for intimate data, but less privacy when we are in public view; and we should allow federal, state and local governments far less privacy in dealings with us.

In examining privacy issues, one name towers over all others: Louis D. Brandeis (1856-1941). Concepts he pioneered over a half century, first as a prominent Boston lawyer, eventually as an influential associate Supreme Court justice (1916-1939), have guided debate, legislation and jurisprudence since.

Concepts of what privacy rights are entitled to legal protection have evolved since the time of the American founding. The Bill of Rights includes the Fourth Amendment, which provides:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

Supreme Court cases establish a "reasonable expectation of privacy" entitled to Fourth Amendment protection. The Supremes extended constitutional protection to birth control in 1965 and abortion in 1973, divining "penumbras and emanations" from a makeshift jurisprudential umbrella consisting of the First, Fourth, Fifth and Ninth amendments. Added legal protections have been extended by statute, erecting a complex edifice of federal and state statutory rights. Torts, largely a creature of state law, established by the mid-20th century four distinct privacy rights, enabling people to seek monetary damages and protection from future invasion. The four privacy torts (civil wrongs) are: false light portrayal, via libel or slander; appropriation of the names or images of others for one's own commercial advantage, as in advertising; intrusion, via various forms of clandestine surveillance conducted without legal authorization; and public disclosure of intimate private facts, such as personal health data.

By the late 1960s privacy issues had come front and center, as did "sunshine" laws that put government activities under more intense public scrutiny. Totalitarian states offer no such protection. After the 1989 fall of the Berlin Wall and subsequent German reunification, the German government opened access to the personal files maintained by the German secret police, the infamous Stasi. Some three million Germans, of the 17 million who lived in the former East Germany, exercised their right to see their personal files.

One famous personage, Olympic figure-skating legend Katarina Witt, told the Daily Mail last year about the extent of her 3,000-page Stasi file:

The trouble started when a civil rights activist claimed in a German newspaper that I was an informer for the Stasi, the secret police, and that I had taken money from them....

In my case, there were boxes of them - boxes upon boxes - 3,000 meticulously compiled pages, all now stored in the official archive. It was unbelievable; intriguing yet horrifying.

There, in front of me, was a detailed account of my life since childhood compiled by anonymous informers, a diary of my entire existence....[E]ven in the silence of my own home, I had never really been alone.

One of the biggest surprises was seeing how young I was when the surveillance started. ‘She's eight years old and she has lots of talent,' was one of the opening entries.

Needless to say, few wish that we head in this direction. The last decade has seen radical improvements in the technologies that capture, store and disseminate myriad types of information about us. Accelerating the need to address matters, the federal government is building a monster database in Utah that is expected to provide the National Security Agency with a yottabyte-1024 (trillion trillion, or one septillion) bytes-of data storage.

To put that number in perspective: A byte is a unit of data storage. A hierarchy of prefixes, with corresponding exponents in mathematical shorthand, has been established to measure capacity: kilo (103) for thousand, mega (106) for million, giga (109) for billion, tera (1012) for trillion, peta (1015) for quadrillion, exa (1018)for quintillion, zetta (1021) for sextillion and yotta (1024) for septillion. A printed page contains about 3 kilobytes. The text of a 200-page book thus contains 600 kilobytes. My iMac's computer hard drive stores 2 terabytes.

The Wall Street Journal reported that Americans now annually generate an estimated 161 exabytes, equal to 37,000 times the volume of data contained in the Library of Congress. A yottabyte database can store some 230 million times the current Library of Congress figure. The New York Times cited an IBM estimate of 2.5 exabytes of new data globally created daily-just over 900 exabytes per year. Further, IBM estimates that 90 percent of global data was created in the past two years, and that data creation will double annually through 2020. Through 2020 this amounts to 3-1/2 doublings, a 12-fold jump in database size. And data storage will surely continue to skyrocket after 2020.

Regarding surveillance of private calls, Brandeis wrote in his famous dissent in Olmstead v. United States (1928), a federal wiretapping case:

The evil incident to invasion of the privacy of the telephone is far greater than that involved in tampering with the mails. Whenever a telephone line is tapped, the privacy of the persons at both ends of the line is invaded and all conversations between them upon any subject, and, although proper, confidential and privileged, may be overheard. Moreover, the tapping of one man's telephone line involves the tapping of the telephone of every other person whom he may call or who may call him. As a means of espionage, writs of assistance and general warrants are but puny instruments of tyranny and oppression when compared with wiretapping.

But pulling privacy policy in the other direction are legitimate national security and law enforcement concerns, such as tracking terror suspects to prevent future attacks, and apprehending criminals. Perhaps the Boston marathon bombing might have been averted; in the event, running down the bombers before they could strike again was made possible by surveillance and tracking data.

Against this stands the famous quote of Benjamin Franklin, perhaps wisest of our Founding Fathers: "Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety."

Parsing Franklin's quote, the adjectives "essential" and "temporary" should be weighed carefully. Not all liberty is essential and not all safety is temporary. Some privacy fits easily into essential liberty. Freedoms embedded in the Bill of Rights are essentials. Appearing at a public event like the Boston marathon, where everyone knows a major public event is being televised, is essential as to one's right to travel there and attend. But it seems hardly so in terms of privacy. As to safety, safety from mass-carnage terrorism and waves of violent crime confers public benefits that transcend temporary societal benefits.

Intimate Personal Data: More Privacy

We need more privacy for our inner life. Justice Louis Brandeis wrote in Olmstead:

The protection guaranteed by the Amendments is much broader in scope. The makers of our Constitution undertook to secure conditions favorable to the pursuit of happiness. They recognized the significance of man's spiritual nature, of his feelings, and of his intellect. They knew that only a part of the pain, pleasure and satisfactions of life are to be found in material things. They sought to protect Americans in their beliefs, their thoughts, their emotions and their sensations. They conferred, as against the Government, the right to be let alone -- the most comprehensive of rights, and the right most valued by civilized men....

The collection of comprehensive personal health data under ObamaCare is a vastly greater invasion of our privacy than call monitoring by intelligence and law enforcement. Yet far less attention has been focused upon this threat. But we should be willing to surrender more privacy in public settings.

Data in Public View: Less Privacy

Anyone strolling in today‘s downtown London is photographed an estimated 300 times per day. This would have horrified Brandeis, who with his co-author, law partner Samuel Warren, sounded the first privacy alarm over unwanted exposure facilitated by new technology-cameras used by press photographers-in their seminal 1890 Harvard Law Review article, The Right of Privacy:

The right of one who has remained a private individual, to prevent his public portraiture, presents the simplest case for such extension; the right to protect one's self from pen portraiture, from a discussion by the press of one's private affairs, would be a more important and far-reaching one. If casual and unimportant statements in a letter, if handiwork, however inartistic and valueless, if possessions of all sorts are protected not only against reproduction, but also against description and enumeration, how much more should the acts and sayings of a man in his social and domestic relations be guarded from ruthless publicity. If you may not reproduce a woman's face photographically without her consent, how much less should be tolerated the reproduction of her face, her form, and her actions, by graphic descriptions colored to suit a gross and depraved imagination....

It remains to consider what are the limitations of this right to privacy, and what remedies may be granted for the enforcement of the right.....But the more general rules are furnished by the legal analogies already developed in the law of slander and libel, and in the law of literary and artistic property....

The right to privacy does not prohibit any publication of matter which is of public or general interest.

Brandeis penned those words 123 years ago, in a world where publicity meant notoriety in a small town, or a larger city, but rarely anything else. Electric illumination was rare, film soon to be born. A world of billions of cellphone cameras, websites, weblogs, television and computer screens, instantaneous global communications and storage forever, was the stuff of science fiction, if even that. Magazine, television, film and online images reveal far more of the human form than was the custom during Brandeis's lifetime.

Though constant surveillance missed several major terror attacks in London, as in Boston video enabled rapid capture of the terrorists. In the trial of neighborhood watchman George Zimmerman for the killing of teenager Trayvon Martin during their tragic encounter, video surveillance could have definitively established whether (though not which) words were first exchanged, who started the fight and how violent and intense the encounter was, the legal predicates for a claim of self-defense. And there would be far fewer post-verdict skeptics.

Data on Government Actions: More Sunlight

The IRS abuses and the impending transfer of intimate personal data to the Department of Health and Human Services as part of implementing ObamaCare, call for new levels of protection against government abuse of its powers, at the expense of the citizenry. In addition to walling off much sensitive personal data, protection should be extended to new categories of interaction between government and the people.

Once again, we can turn to Brandeis, who wrote in a 1913 article for Harper's Weekly, What Publicity Can Do:

Publicity is justly commended as a remedy for social and industrial diseases. Sunlight is said to be the best of disinfectants; electric light the most efficient policeman. And publicity has already played an important part in the struggle against the Money Trust. The Pujo Committee has, in the disclosure of the facts concerning financial concentration, made a most important contribution toward attainment of the New Freedom. The battlefield has been surveyed and charted. The hostile forces have been located, counted and appraised....But there should be a further call upon publicity for service. That potent force must, in the impending struggle, be utilized in many ways as a continuous remedial measure.

Brandeis was addressing abuses by the financial titans of Wall Street. More to the point today is how the IRS would have treated hundreds of conservative organizations were all its dealings with them videotaped. An added safeguard would be to allow those with whom the government deals to independently video- or audio-record encounters, to guard against government alteration or destruction of inconvenient portions of sole-source records. Handheld cameras and camcorders make these ideas readily achievable.

The police should not be permitted to confiscate equipment recording of encounters. If a video or audio record is misleading, courts can always declare them inadmissible as evidence. Exceptions can be made in extraordinary circumstances, such as hostage situations and other grave threats to public safety. A record of normal interactions would act as a safeguard against blackmail, trumped-up perjury charges and violent abuse by public officials.

If the government needs a monster database to watch us, we need a monster database to watch the government.

There are of course instances where confidentiality of government proceedings is essential. The most obvious example is national security matters. (Recent disclosures of intelligence data collection by Edward Snowden constituted spying, not legitimate monitoring of government activity.) Law enforcement investigations cannot be conducted in public, lest targets be alerted and hence destroy evidence or take flight. Access to any records kept of these matters should require a clear showing by petitioners of compelling public interest in disclosure.

In sum, valid privacy concerns must be addressed. But reassessment is overdue as to what is truly private, what is properly public and what dealings between regulators and the regulated must be on public record. The writings of Brandeis, preeminent in the field of privacy, offer us a policy lodestar. Today's privacy controversies invite us to rethink existing balances between privacy and disclosure, given emerging trends in technology and regulation.

Mr. Wohlstetter is the author of "Sleepwalking With the Bomb" (Discovery Institute Press, 2012). Follow John on twitter at @JohnWohlstetter